What are GLP-1 drugs and how could they prevent disease?
GLP-1 receptor agonists are medications that mimic a natural hormone that regulates blood sugar and appetite. They are already approved for treating type 2 diabetes and obesity, but their potential for preventing disease goes far beyond that. The largest and most comprehensive study here, which tracked over 215,000 people taking GLP-1 drugs compared to other diabetes medications, found that users had a lower risk of 42 different health outcomes, including substance use disorders, psychotic disorders, seizures, Alzheimer's disease, dementia, heart attacks, and several respiratory infections [5]. This suggests these drugs could be powerful tools for preventing a wide range of chronic diseases, not just managing existing conditions.
A key part of their preventive power comes from weight loss. In a randomized trial of the oral GLP-1 drug orforglipron, people with obesity lost 9.4% to 14.7% of their body weight over 36 weeks, compared to just 2.3% with placebo [2]. Since obesity is a major risk factor for heart disease, cancer, and liver disease, this weight loss alone is a significant preventive benefit. The same study found that 46% to 75% of people on the drug achieved at least 10% weight loss, a threshold known to improve many health markers [2].
Can GLP-1 drugs prevent cancer and liver disease?
The evidence is mixed but promising for cancer prevention. A nationwide Danish study of over 14,000 men found that those taking GLP-1 drugs had a 20% lower risk of developing prostate cancer compared to those on insulin, with an even stronger 53% risk reduction in men over 70 [4]. However, a large French study of over 2,500 thyroid cancer cases found that using GLP-1 drugs for 1-3 years was associated with a 58% higher risk of all thyroid cancers and a 78% higher risk of medullary thyroid cancer [7]. This means that while these drugs might protect against some cancers, they may increase the risk of others, so they are not yet recommended for general cancer prevention.
For liver disease, the evidence is stronger and more consistent. A review of multiple studies concluded that GLP-1 drugs are beneficial for nonalcoholic fatty liver disease (NAFLD), a condition that affects millions and can lead to cirrhosis [8]. The review notes that the FDA has approved semaglutide for obesity, and that GLP-1 drugs are one of the few medication classes that can reverse steatohepatitis (liver inflammation) in people with NAFLD [8]. This positions them as a practical preventive tool for liver disease in high-risk groups like people with obesity or type 2 diabetes.
What are the risks and limitations?
The most common side effects are gastrointestinal, which are usually mild to moderate but can cause people to stop the medication. In the orforglipron trial, 10% to 17% of participants discontinued the drug due to side effects like nausea and vomiting [2]. More serious risks include intestinal obstruction, which a real-world study found was 3.5 times more common in GLP-1 users [6], and pancreatitis [5]. These risks mean that GLP-1 drugs are not suitable for everyone and require medical supervision.
There is also the question of individual response. A genome-wide study of over 4,500 people found that genetic variants in the ARRB1 gene can affect how well a person responds to GLP-1 drugs, with some people experiencing 30% greater blood sugar reduction than others [3]. This means that in the future, genetic testing could help identify who will benefit most from these drugs for prevention. Importantly, a large Swedish-Danish study found no increased risk of suicide or self-harm with GLP-1 use, addressing a major safety concern [1].
About These Sources
This answer is built on 8 peer-reviewed studies — published from 2021 to 2025, 2 from 2024 or later, 7 in Q1 journals, collectively cited 1,151 times — selected as the most relevant from 9 studies that passed quality screening, drawn from 56 papers retrieved from a database of over 500 million.
Sources used in this answer
GLP-1 Receptor Agonist Use and Risk of Suicide Death
In a cohort study of over 124,000 GLP-1 users in Sweden and Denmark, there was no increased risk of suicide death, self-harm, or depression compared to users of SGLT2 inhibitors, with suicide deaths being rare (0.23 per 1,000 person-years).
Daily Oral GLP-1 Receptor Agonist Orforglipron for Adults with Obesity
In a phase 2 randomized trial of 272 adults with obesity, the oral GLP-1 drug orforglipron led to 9.4% to 14.7% weight loss over 36 weeks, with 46-75% of participants losing at least 10% of their body weight, compared to 9% on placebo.
Pharmacogenomics of GLP-1 receptor agonists: a genome-wide analysis of observational data and large randomised controlled trials
A genome-wide analysis of 4,571 adults with type 2 diabetes found that genetic variants in ARRB1 and GLP1R were associated with up to 30% greater HbA1c reduction on GLP-1 drugs, suggesting genetic testing could guide prescribing.
Potential preventive properties of GLP-1 receptor agonists against prostate cancer: a nationwide cohort study.
A Danish nationwide cohort of over 14,000 men found that GLP-1 use was associated with a 20% lower risk of prostate cancer compared to insulin, with a 53% risk reduction in men over 70.
Mapping the effectiveness and risks of GLP-1 receptor agonists
The largest study here, covering over 215,000 GLP-1 users in the VA system, found reduced risks of 42 outcomes including Alzheimer's disease, substance use disorders, and heart attacks, but increased risks of gastrointestinal disorders, pancreatitis, and kidney stones.
A potentially serious adverse effect of GLP-1 receptor agonists
A review reports that real-world data show a 3.5-fold increased risk of intestinal obstruction with GLP-1 use, and animal studies found the drugs increased small intestine length by up to 43%.
GLP-1 Receptor Agonists and the Risk of Thyroid Cancer
A French nested case-control study of 2,562 thyroid cancer cases found that 1-3 years of GLP-1 use was associated with a 58% higher risk of all thyroid cancers and a 78% higher risk of medullary thyroid cancer.
The Emerging Role of Glucagon-like Peptide-1 Receptor Agonists for the Management of NAFLD
A review concludes that GLP-1 drugs are beneficial for nonalcoholic fatty liver disease (NAFLD), with semaglutide approved for obesity and evidence that these drugs can reverse steatohepatitis in biopsy-proven cases.